docs: def gc(coeff, mag):
      """
      Returns the set of coefficients to be used for the calculation of GM
      as a function of earthquake magnitude
  
      :param coeff:
          A dictionary of parameters for the selected IMT
      :param mag:
          Magnitude value
      :returns:
          The set of coefficients
      """
      if mag > 6.5:
          a1ca = coeff['ua']
          a1cb = coeff['ub']
          a1cc = coeff['uc']
          a1cd = coeff['ud']
          a1ce = coeff['ue']
          a2ca = coeff['ia']
          a2cb = coeff['ib']
          a2cc = coeff['ic']
          a2cd = coeff['id']
          a2ce = coeff['ie']
      else:
          a1ca = coeff['a']
          a1cb = coeff['b']
          a1cc = coeff['c']
          a1cd = coeff['d']
          a1ce = coeff['e']
          a2ca = coeff['ma']
          a2cb = coeff['mb']
          a2cc = coeff['mc']
          a2cd = coeff['md']
          a2ce = coeff['me']
      return a1ca, a1cb, a1cc, a1cd, a1ce, a2ca, a2cb, a2cc, a2cd, a2ce